1. Field of the Invention
The invention relates to a projection module and an electronic device. More particularly, the invention relates to a projection module, wherein a lens group is fixed on a chassis, and an electronic device using the same.
2. Description of Related Art
A projection apparatus may project images onto a large screen to facilitate more people watching the images displayed on the screen at the same time. Therefore, the projection apparatus is generally used in public places such as companies, schools, or other places. Moreover, as family-used display products trend to be large-scaled, the projection apparatus is also widely used in general families, and becomes a commonly used electronic product in people's daily life.
With development of technology, electronic products are developed to have high speed, high performance, and design features of lightness, slimness, shortness and smallness. In this case, pico projectors (or mini projectors) have become a main stream in the market of personal digital products. Generally, a light source of the pico projector applies a light emitting diode (LED) or other solid state light sources to improve a total lumen of the pico projector, so as to improve a brightness of projected images. After the pico projector is produced, a size of the pico projector including a battery is similar to a size of a general mobile phone in the market. Even, the pico projector may be integrated in the mobile phone. Therefore, the pico projector has advantages of portability and no restriction of usage locations.
However, in a pico projector, a lens module of the pico projector is integrated, and then is disposed on the chassis, and when a focal length of the lens module is adjusted, the lens module is moved relatively to the chassis. Since shapes of the chassis and the lens module are complicated, it is not easy to design a mechanism having both features of a sealed state and a smooth movement, so that a gap is probably formed between the lens module and the chassis, and therefore dustproof capability between the lens module and the chassis is poor. Moreover, when the lens module is moved relatively to the chassis due to adjustment of the projection focal length, the appearance of the chassis may cause a visual harassment for the user.
Moreover, to ensure that the lens module is capable of being moved relatively to the chassis, in the mechanism, a moving space required by the lens module is generally reserved on the chassis. However the advantages of lightness, slimness, shortness and smallness of the pico projector or the mobile phone integrated with the pico project may be lost due to the moving space reserved on the chassis.